Work gauge for machine tools



March 10, 1953 w, ESCHENBURG 2,630,845

WORK GAUGE FOR MACHINE TOOLS Filed July 7, 1948 3 Sheets-Sheet lINVENTOR William A. Eschenburg BY/MJ/W Attorneys w. A. ESCHENBURG WORKGAUGE FOR MACHINE TOOLS March 10, 1953 Filed July 7, 1948 3 Sheets-Sheet2 INVEN TOR Wi/l/am A. E schenburg AI for/rays March 10, 1953 w. A.ESCHENBURG WORK GAUGE FOR MACHINE TOOLS 3 Sheets-Sheet 5 Filed July7,1948

INVENTOR William .4. E schenburg By 9 %W A from eys Patented Mar. 10,1953 WORK GAUGE FOR MACHINE TOOLS William A. Eschenburg, Freeport, IlL,assign'or to Rockwell Manufacturing Company, Pittsburgh, Pa., acorporation of Pennsylvania Application July 7, 1948, SerialgNo. 37,461

2 Claims. 1

This invention relates to work gauges for machine tools, and moreparticularly to a work gauge or fence assembly for circular sawmachines, of the type disclosed in the patent to Arthur J. Aumann2,265,335 issued December 9, 1941.

It is the general object and purpose of the present invention to providecertain improvements in this patented rip gauge assembly consisting ofan. improved construction and assembly of the rear end supportingbracket for the gauge bar and the means for locking said bracket infixed adjusted position relative to the table.

With the above and other objects in view, the

invention resides in the improved work gauge for machine tools. and inthe form construction and relative arrangement of its several parts aswill hereinafter be more fully described, illustrated in theaccompanying drawings and subsequently claimed in the sub-joined claims.

In the drawings wherein I have shown one preferred practical embodimentof my invention, and in which similar reference characters designatecorresponding parts throughout the several views:

Figure 1 is a side elevation illustrating a selected embodiment of theinvention in the form of a rip fence assembly for a circular saw;

Figure 2 is a top plan view thereof;

Figure 3 is a side elevation on an enlarged scale, certain parts beingshown in section and others broken away and the rip fence or gauge barbeing locked at its front and rear ends in adjusted position relative tothe machine table;

Figure 4 is a similar view of the front end looking device with the handoperated'lever disposed in its unlocking position;

Figure 5 is an exploded perspective view of the front end supportingbracket for the gauge bar and parts associated therewith;

Figure 6 is an enlarged fragmentary plan View showing the mounting andarrangement of the magnifying lens on the adjustable front end bracket;

Figure 7 is a sectional view taken substantially on the line l'l ofFigure 6; and

Figure 8 is an exploded perspective view of the adjustable rear endbracket and parts of the locking device associated therewith.

Referring in further detail to the drawings, I have illustrated apreferred form of the invention as embodied in a rip gauge or fenceassembly mounted on the work table I!) of a circular saw l2 whichextends upwardly above the table surface through an insert plate I4mounted in the table. The table is mounted in the usual manner uponsuitable supportingmeans I6 and may be provided in its upper surfacewith the usual guide grooves, for a miter gauge. V

The rip gauge or fence assembly includes the gauge bar 20 ofsubstantially inverted U-shaped form in cross-section and of sufficientlength to extend across the surface of the table I!) and beyond thefront and rear edges thereof, said bar beingpclosed at each end. Thefront end of this gauge bar is mounted upon a supporting bracket 22 in amanner to be later explained, said bracket being longitudinallyadjustable upon a guide rail 2 extending along the front edge of thetable If and rigidly fixed in spaced parallel relation thereto by meansof suitable bolts 26. Preferably, this guide rail is of tubularcylindrical form.

A supporting bracket 28 for the rear end of the gauge bar 26 issimilarly mounted for longitudinal sliding movement upon the cylindricalsupporting rail 30 rigidly fixed to the rear edge of the table if! bybolts 32. The brackets 22 and 28 support the gauge bar 26 on the guiderails 24 and 38 with thelower open side thereof in clearance relation tothe upper surface of the table H].

As seen in Figure 2 of the drawings, the front supporting bracket 22 isof hollow elongated construction and extends laterally from each side ofthe gauge bar 26 and together therewith forms a T head assembly. Thisbracket at its upper end is provided with longitudinally spaced threadedopenings to receive the threaded axially projecting studs on the lowerends of the vertical posts 34 which extend upwardly from the bracketwithin the end of the gauge bar 2! and at their upper ends are providedwith reduced axial extensions 38 projecting above the gauge bar throughopenings if] in the top wall thereof. The upper ends of the extensions38 are threaded "and receive cap nuts 42 and locking washers 44 for saidnuts. The openings are slightly elongated transversely of the gauge bar.Thus the gauge bar may be angularly adjusted relative to the bracket 22in a horizontal plane and then rigidly fixed in its adjusted position bythe nuts 62 in accurately parallel relation with the plane of the sawblade l2.

Within a central hollow body portion 46 (Figure 5) of the bracket 22 avertically disposed locking lever 48 is mounted. As herein shown, thislever, substantially midway between its ends, is provided with anenlarged hub portion 5!! having a large diameter bore or opening 52relative to the diameter of a pin 54 which is disposed through saidopening and fixed in any suitable manner in the opposite side walls ofthe body portion 45 of the bracket. The pin 52 is axially parallel withthe guide rail 24 and located above and forwardly of said rail.

Below the pin 54 lever 48 is provided with an arcuate clamping surface56 which engages the front peripheral surface of the guide rail 24 inthe locking position of said lever. Below the surface 55, the lever 48carries an adjustable plug 58 having its axis disposed at right anglesto the axis of rail 24. The plug is locked in its adjusted position bymeans of the pin 68 and a screw 62 threaded in the lower end of avertical bore in the lever and coacting with said pin.

The front end of plug 58 is engaged by a cam or eccentric 54 rotatablysupported upon a pin 86 suitably fixed in the bracket and axiallyparallel with the pin 54. An actuating rod 68 has a threaded connectionat one end with the eccentric 54 and is frictionally locked againstcasual turning movement relative to the eccentric by means of the spring7%]. This rod 63 extends outwardly and forwardly through an arcuate slotI2 in the front wall of the bracket 22 and is provided at its forwardend with a suitable hand knob I4.

Below the plug 58 a coiled spring 16 has its opposite ends seated insuitable recesses in the lever 48 and the rear wall of the bracket bodyrespectively. This spring yieldingly holds the forward end of plug 58 incontact with the periphery of eccentric IE4 and by the axial adjustmentof the plug, the clamping pressure applied by the lever against the rail24 may be properly regulated.

The rear end supporting bracket 23 for the gauge bar 20 also carries adevice for locking the gauge bar in its adjusted position to the rail Asherein shown, this rear bracket 28 is relatively narrow and has a majorwidth substantially equal to the width of the gauge bar 221. The end ofthe bar 20 is rigidly secured upon the rectangular base portion 18 ofthe bracket by means of a plurality of screws 88. This bracket base hasa forward saddle portion provided with an arcuately concave surface 82slidably seated upon the upper side of the guide rail 3! Rearwardlythereof the base 18 is formed with a vertically extending rectangularguide opening 84 for the locking rod 86 which has a forwardly projectingcurved or hooked lower end portion ill for clamping engagement againstthe underside of the rail 36. Above the base I8, the rod 85 extendsaxially upward within a vertical tubular boss or portion 88 of thebracket, said tubular portion being integrally connected at the frontside thereof throughout its length with the base I8 by spaced parallelwebs 96 between which the lower end portion of the tube wall is providedwith a vertically extending slot 92.

A bell crank lever 94 is pivotally mounted upon a pin 96 suitably fixedat its ends in the bracket webs 9B. The lower horizontal arm 98 of thislever extends rearwardly through the slot 92 and within the bifurcatedupper end I08 of the locking rod 86 and in contact with the under sideof a pin I82 connecting the spaced arms of said bifurcation. The rearend bracket 28 and locking device thus constitutes a sub-assembly unitthat may be readily handled as a single element in a"- sembly of the ripgauge or fence.

A compression spring I84 bears at its upper end against the top wall ofthe gauge bar 29 and extends downwardly therefrom into the upper end ofthe tubular portion 88 of bracket 28. A bearing cap member I08 withinthe lower end of this spring has contact upon the upper end of thelocking rod 86 tending to urge said rod downwardly and rock lever 94 inan anti-clockwise direction and releasing the clamping pressure of thelower end 37 of said rod against the guide rail 32.

It will be noted that the uppermost portions of bracket 28 are whollyenclosed within the bar 23 without protruding fastening elements, suchas bolt heads, so that in feeding the work to the saw the operators handmay freely slide over the surface of the gauge bar.

For the purpose of actuating the front and rear locking devices to theirlocking positions in successive order in a single oscillation ofeccentric BS in one direction, the levers 48 and 94 are interconnectedby a motion transmitting means, which in the present instance comprisesa red sea extending longitudinally within the gauge bar 2'8. This rod atits rear end is flattened out transversely and has a longitudinallyextending slot IIB in the flattened portion receiving the upper end ofthe vertical arm I I2 of bell crank lever 92. Lever arm H2 has a notchIt in its rear edge receiving the extremity of the rod IE8 at the rearend of slot H9.

The gauge bar 2:: in spaced relation from its forward end wall isinternally formed with longitudinally spaced transverse webs I I6 which,when the bar is assembled on bracket 22, are positioned between thevertical posts 32, on said bracket. These webs are provided withrelatively large openings H8 in axial alignment with relatively diameteropenings I28 in the posts as so as to freely pass the flattened end ofrod I88. The forward end of rod I08 extends through the opening I28 inthe rear post 34 and opening H8 in the adjacent web H6 and has athreaded terminal portion I22 engaged with the internally threaded endof the longitudinal bore I253 in a support sleeve I24 rotatably mountedin the opening IIB of the forward web H6 and a similar opening 28 in theforward end wall of the bar 22. A spring I32 in the bore I urges the rodHi8 and sleeve I24 in opposite directions to frictionally lock theadjustable sleeve I24 to the threaded end I22 of rod I08.

Rearwardly of sleeve I24. the upper end of locking lever 48 isbifurcated, as at I32 (Figures 2 and 5), and loosely straddles the rodI28, there being suflicient lateral play to permit of the angularadjustment of gauge bar 20 relative to bracket 22 in the manner abovedescribed, for which purpose also the large diameter openings I22 inposts 34 are provided.

When the operating handle 68 and eccentric (i i are in the positionshown in Figure 4 of the drawings, the brackets 22 and 28 together withgauge bar 20 may be freely moved along the guide rails 24 and by meansof a pinion I34 (Figure 2) on one end of shaft I36 journalled in asuitable bearing I38 provided on bracket 22 and in constant engagementwith rack teeth I formed on the under side of rail 24.

In the assembly of gauge bar 20 and the front and rear brackets 22 and28, the posts 32 are connected with the front bracket 22. The forwardend of the gauge bar is then mounted on the bracket and secured by capnuts 42. The assembled rod 108 and the sleeve I24 are now inserted inthe gauge bar from the front end thereof, after which the upperstructure of the rear bracket 28 with its assembled locking device andcap I06 and spring I04 in place is inserted upwardly into the rear endof the gauge bar. This assembly is facilitated by the longitudinallyelongated slot II II in the rear end of rod it through which the upperend of lever arm II2 may be readily inserted. The bracket base is thenshifted rearwardly to position the rear extremity of rod I03 in notchII4 of the lever arm and the base is rigidly secured to the bar by meansof screws 85, thus completing the assembly.

In the operation of the above described assembly, assuming that thefence or gauge bar 20 has been properly adjusted on supporting bracket22 after the front and rear brackets have been slidably engaged upon therails 24 and respectively to position the bar 20 across the surface ofthe work table in parallel relation with the plane of the saw blade I2and with operating handle 58 and locking lever 48 in the position shownin Figure 4 of the drawings; shaft I36 is first rotated to move thebrackets and gauge bar longitudinally along the guide rails and positionthe bar 20 in predetermined laterally spaced relation from the sawblade. The handle rod 68 is now swung downwardly from the position ofFigure 4 to that shown in Figure 3, thus rotating the eccentric E4 in aclockwise direction. In the first portion of this movement of theeccentric, by reason of its contact with the plug 58, the lever d8 islifted out of contact with pin 54 and is rocked in a clockwise directionagainst the resistance of spring I6 until the surface 56 on the leverhas clamping contact with the surface of guide rail 24 to square thefence with rail 24 and hold the bracket 22 against longitudinal shiftingmovement thereon from its adjusted position. The upper forked end I32 oflever 48 is thus brought into bearing contact with the inner end ofsleeve I24. In the further rocking motion of eccentric 64 with continuedaxial pressure against the plug 58 in a plane below the guide rail 24the lever then fulcrum on said rail about the axis thereof and isfurther moved in the clockwise direction, thus applying axial pressureagainst the inner end of sleeve I24 and moving the connecting rod Illato the right. Thus, pivotal motion is transmitted to bell crank lever 94of the rear locking device in a clockwise direction, and arm 98 of saidlever bearing upwardly against pin I52 moves locking rod 85 upwardlyagainst the resistance of spring his so that the lower hooked end ofsaid rod is tightly is clamped against the under side of the rail tothus lock the bracket 28 and the rear end of the bar 2!? againstlongitudinal movement on said rail from the adjusted position.

The lost motion connection between the upper end of lever 48 and rod IE3assures the effective operation of the rear locking device only afterlateral squaring motion caused by the locking engagement of lever 48with the front guide rail 24 has ceased so that the initiallyestablished parallel relationship between the bar 20 and saw blade I2will be preserved when both ends of the bar are finally rigidly lockedto the respective guide rails. It is to be particularly noted that inthe clockwise movement of lever 48 and the actuation of the rear lockingdevice by rod I03, lever 48 is out of contact with the fulcrum pin 54thus minimizing the manual efiort required to rotate eccentric 54 androck said lever about the axis of guide rail 24.

To release the gauge bar for longitudinal adjustment along the guiderails, the handle rod 88' is swung upwardly from the position of Figure3 and in the first portion of the counterclockwise rotation of eccentric64, a substantially simultaneous reaction of the springs I6 and I04 ofthe front'and rear locking devices occurs and spring H5 moves the lowerend of lever to the right, maintaining contact of plug 58 with theperiphery of the eccentric and disengaging the clamping surface 56 ofthe lever from the periphery of the rail 24. At the same time, springI84 of the rear locking device moves the rod 88 downwardly out ofclamping engagement with rail 30, and through bell crank lever 94 movesrod I98 to the left. In the further counter-clockwise rotation ofeccentric 64, the spring 76 functions independently of spring I04causing the lower end of lever 48 to fulcrum about the point of contactof plug 58 with the periphery of the eccentric, and thus moving theupper portion of the lever in a counterclockwise direction and finallycontacting the hub portion 550i the lever with the pin 54 as the upperforked end of the lever moves to the left out of contact with the innerend of sleeve I24 to the position seen in Figure 4 of the drawings. Inthis position, the angle of repose of the lever 48 is such that thesurface 56 thereof is in slightly eccentric relation to the peripheralsurface of rail 24 and the point of intersection of the axis of plug 58with. the periphery of eccentric 64 is slightly lower than when thelever is in the locking position of Figure 3. Otherwise, it will benoted that horizontal planes intersecting the axes of plug 58 and pin 54are substantially equidistantly spaced below and above a horizontalplane intersecting the axis of rail 24.

As will be evident from the above description, by rotating the sleeveI24 and adjusting the same axially on the end of rod Iilt, the inner endof said sleeve may be variably spaced from the end I32 of lever 48 todetermine the elapsed time interval between the locking of bracket 22 bysaid lever to rail 24 and the locking of the rear end bracket 28 toguide rail 35 by the clamping rod 85.

I have also provided improved means associated with the front bracket 22which enables the operator to rapidly and accurately adjust said bracketalong the guide rail to position the fence or gauge bar 2!? across thetable 'surface in a desired predetermined spaced relation from the sawblade. To this end, the top of the bracket '22 at one side of the gaugebar 29 and above rail 24 is formed with an upstanding boss Hi2 which ishollow and preferably elongated longitudinally of the guide rail 25. Theupper end face of this boss lies in a plane slightly below the topsurface of the table II! and a magnifying lens M l, also of elongatedform, is housed wholly within this hollow boss, said lens having upperand lower convex surfaces I4e and hit respectively (Figure 7), thelatter being centrally provided with a transversely extending hair lineI50 and disposed immediately adjacent the scale graduations I52 on theupper surface of rail 24.

The lens block I44 may be formed of cast Lucite or other suitablematerial and the lower curved surface thereof is of major convexity inorder to avoid distortion. The opposite side edges of the lens areformed with shallow longitudinally extending grooves I54 and it isadjustably supported in the boss I42, in clearance relation to theopposite side walls thereof, by means of longitudinally spaced adjustingscrews I56 threaded in one of said side walls in contact with the basewall of one of the grooves I54 and a single set screw l58 threaded inthe opposite side wall of the boss contacting the base wall of the othergroove 54, and located in a vertical plane substantially midway betweenthe adjusting screws 55. It will thus be evident that by loosening oneof the screws I56 and tightening the other against one end of the lensMd, the lens may be angularly adjusted in a horizontal plane withrespect to the walls of the boss I42 and to the longitudinal axis of therail 24 to accurately position the hair line 150 on the curved surfaceHit in parallel relation to the scale graduations 152 on the rail. Itwill be noted that the lens ltd is disposed wholly below the top surfaceof boss Hi2 so that it will not be damaged or scratched by work fed tothe saw which at times may rest upon the boss 42.

Preferably the part of the bracket casting overlying rail 24 having theboss 142 formed thereon is provided with internal circumferentiallyextendin ribs 158 at opposite ends of said boss. These ribs, slidablycontacting the surface of rail 24, maintain a permanently spacedrelationship of the lower curved surface I48 of the lens from the scalegraduations 152 on the rail. The lower edge portions of the ribs Hill inalignment with the scale graduations are preferably slightly recessed asat 162 and in clearance relation to the graduated surface of the rail toavoid possible obliteration of such graduations by friction in thelongitudinal adjustment of the bracket upon the guide rail 24.

From the foregoing description and the accompanying drawings, it will beseen that the present invention provides an improvement in the rip fenceor work gauge assembly of the above mentioned issued patent. It has beenfound that such improvements contribute to greater ease and rapidity inthe assembly and accurate adjustment of the fence or gauge bar and thelocking thereof in such adjusted position in rigidly fixed relation tothe work table and saw blade. While the present disclosure includespreferred structural examples of the gauge bar and the front and rearend supporting brackets therefor, it will be understood that suchdisclosure is largely suggestive, and in the application of the presentinvention to various types of machine tools may require more or lessmodification as to their component elements as well as the method andmeans for slidably mounting the brackets on the work table. However, thedisclosed construction provides a simple and inexpensive assembly ofmaximum stability with reliable and efficient operation of the fencelocking means.

The invent-ion may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiment is therefore to be considered in all respects 4.

as illustrative and not restrictive, the scope of the invention beingindicated by the appended claims 8 rather than by the foregoingdescription, and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States LettersPatent is:

1. In a work gauge assembly, a gauge bar of inverted U-form incross-section closed at each end and open for at least a substantialdistance at each end of its lower edge, brackets closing the ends ofsaid open lower edge for slidably supporting the ends of said bar uponguides at opposite sides of a machine tool table, a device carried byeach bracket to releasably lock said brackets in adjusted position onthe respective guides, motion transmitting means operatively mounted inthe gauge bar and interconnecting said devices, said means including arod extending longitudinally within the gauge bar and provided with aslot in one end terminating within said bar, and one of said devicescomprises an upstanding, flanged boss carried by its associated bracketand housing a movable clamp member and having an actuating bell crankrocking lever pivotally mounted thereon with one arm engaging said clampmember and the other arm paralleling said boss, whereby said device andits bracket provide a sub-assembly adapting said device to be insertedinto the open lower edge of said gauge bar at one end thereof to engagesaid other arm in the slot in said rod in the assembly of said bracketwith the gauge bar.

2. A work gauge assembly as defined in claim 1, wherein saidsub-assembly comprises a base formed to slidably engage its associatedguide, a vertical cylindrical boss providing an upwardly opening springconfining bore and disposed with in the gauge bar and connected byspaced webs with the base to reinforce said cylindrical boss, pivotmeans carried by said webs supporting said rocking lever and having anarm engaged in said slot of said rod, a spring pressed locking barvertically movable in said cylindrical boss and operatively connectedwith said second arm of said lever.

WILLIAM A. ESCHENBURG.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 354,740 Rogers Dec. 21, 18861,090,432 Vetter Mar. 17, 1914 2,043,625 Lindner June 9, 1936 2,111,977Lindner Mar. 22, 1938 2,265,335 Aumann Dec. 9, 1941 2,325,082 Tautz July27, 1943 2,556,548 Modderman June 12, 1951

